deep sky sequencer and asteroids observation

[cyrille.de.brebisson]

Hello,

Is it possible to use the deep sky sequencer to observe a list of asteroids?
I do not see asteroids in the "target" catalog.

Thanks
Cyrille

[cyrille.de.brebisson]

Hello,

What I am trying to achieve is a double loop of:
for count = 0 to 10 do
for each asteroid in a list
go to position
pause for 5s for backlash to settle
take a 2s shot, platesolve and resync
pause 5s for backlash
start guiding
pause 5s for guiding to become active
take a 60s shot saved in a file name asteroid_count where, in best case scenario asteroid is the actual name,
in worse case scenario it's a number or the coordinates, and count is the loop count.
next
next

What would be the best way to acheive this?
I know that asteroid move, but I can still get coordinates that will be in the field even after the 2h that the sequence will take.

Thanks,
Cyrille

[Jean-Francois]

Hello Cyrille,

If you can generate a list of "targets" ... then it does not matter if the targets are stars, galaxies or other objects in the sky.

The point is to have the J2000 coordinates of the asteroids for the observation time.
SharpCap does not have (yet ) a catalogue of asteroids and comets. I mean that SharpCap calculates the position of the asteroids/comets.

In the place of the "list of asteroids", you can have a "list of coordinates". The point is to calculate these coordinates in advance.
If it is a few asteroids, then you can do it manually with different planetarium software.
If it is a large number of asteroids ... maybe some script on the JPL (Horizon) webpage that can automatize the process.

Note that you have fast all the tools for doing it by yourself ... with the scripting language and the ASCOM Novas tools.

Regards,
Jean-Francois

[admin]

Hi,

Jean-Francois is correct - the key is to build a list of co-ordinates in a text file in some other tool and then use the 'Repeat for each RA/Dec co-ordinate in co-ordinate list file' step to work through that list (see https://docs.sharpcap.co.uk/4.1/#Repeat). The list can also include the name of the object before the RA/Dec on each line, which will get the capture files named correctly.

I have looked at having some part of the MPC data in SharpCap and calculating the positions from the orbits, but there are a couple of issues with that

1) The MPC data needs updating regularly - probably far more often than most people update SharpCap, so that problem would be solved
2) The main MPC list is far too large to include, so it would have to be a cut down sample, but there is no obvious way to separate the 'interesting' from the rest to cut down the list in a sensible manner.

cheers,

Robin

[admin]

Hi folks,

as a first step in this direction, I have added a sequencer step to SharpCap in the very latest update (4.1.13534) that gives the ability to GOTO an asteroid/comet target using the MPCORB data (a single line cut from MPCORB.DAT or one of the special interest versions) - ie

Code: Select all

00944   10.55  0.15 K2555 171.00031   56.56738   21.38991   42.54803  0.6622544  0.07189173   5.7281812  0 MPO887301  1971  31 1920-2024 0.72 M-v 3Ek MPCLINUX   0000    (944) Hidalgo            20240512

This step will set the target name appropriately (to '(944) Hidalgo' for the above data) and calculate and GOTO the current position of the target based on the MPC data.

I am using 'AASharp' for the elliptical orbit calculations, which is a port of the classic PJ Naughter AA+ library (which is, itself based on Jean Meuss' book, "Astronomical Algorithms."). Hopefully that is doing a good job - the figures look about right - let me know if you encounter any significant errors.

I have some ideas for future improvements to this, including

* A repeat step to allow multiple asteroids to be targeted by specifying multiple lines of MPC data
* An interactive UI to allow the GOTO to happen by pasting in the MPC data or searching by name/id (maybe this would require online access to the MPC website search API)
* Annotation in the deep sky annotation (but that would require some/all of MPCORB.DAT)

I will probably not push any of these forward just yet - I will wait to see what interest/discussions/bugs/problems the new sequencer step throws up first.

cheers,

Robin

[carlomuccini]

Thanks!
That was just what we needed.

Would it be possible to have an example of a small script that does the GOTO, 1-s exposure, Sharpsolve, resets the time before the Sharpsolve, executes the exposure, and repeats with a second asteroid?
Thanks so much again.

Carlo

[admin]

Something like this will do it for a single asteroid

Code: Select all

SEQUENCE
    LOAD PROFILE Asteroids
    PRESERVE CAMERA SETTINGS
        SET EXPOSURE TO 1
        MOUNT GOTOMPCORB "00944   10.55  0.15 K2555 171.00031   56.56738   21.38991   42.54803  0.6622544  0.07189173   5.7281812  0 MPO887301  1971  31 1920-2024 0.72 M-v 3Ek MPCLINUX   0000    (944) Hidalgo            20240512"
        MOUNT SOLVEANDSYNC
    END PRESERVE
    CAPTURE 5 FRAMES REQUIREGUIDING False
END SEQUENCE

This assumes that you have a saved camera profile called 'Asteroids' that will set the camera up in the right format (MONO16?), gain, offset, etc. It then temporarily sets a 1s exposure, does the GOTO and then will plate solve + recenter the target. After that the end of the 'PRESERVE CAMERA SETTINGS' block puts the exposure back to the value loaded from the profile and 5 frames are captured.

To capture multiple targets, put more chunks like this near the end (just before the 'END SEQUENCE')

Code: Select all

    PRESERVE CAMERA SETTINGS
        SET EXPOSURE TO 1
        MOUNT GOTOMPCORB "<MPC DATA FOR SECOND TARGET>"
        MOUNT SOLVEANDSYNC
    END PRESERVE
    CAPTURE 5 FRAMES REQUIREGUIDING False

cheers,

Robin

[carlomuccini]

Thanks! Very interesting.

I currently use a software program I developed to download and manage asteroids with MPCORB.DAT data.
I create a list of asteroids I'm interested in and create a custom file for Skymap.
If you don't plan on developing this part soon, I'll create a small function to generate the sequence for all the asteroids I'm interested in.
Thanks again, you've made Sharpcap an indispensable software program.

Carlo

[admin]

Hi Carlo,

adding an extra step that would repeat for multiple lines of MPCORB data in a file would be pretty simple, which would in turn simplify the sequence building as you could just have one sequence file and re-generate the list file with new contents in it.

It would be good to get a bit of feedback on how the existing step is working (are the calculations right, for instance!) before I do the next stage though... Best to check we can walk before running

cheers,

Robin

[carlomuccini]

Of course, I completely agree with you.

The problem with sequencing is doing it manually.
If I need to image just one asteroid, I do the GOTO with the planetarium program; but if there are 5 or 6 asteroids and I have to take 5 minutes of exposure for each, then GOTO the second, etc., and then start again from the first, it becomes a tedious task.
This is where sequencing becomes extraordinarily useful.

In the meantime, I've created a small program that creates the ad-hoc sequence for me, starting from a selected number of asteroids.
I recreate the sequence every time, but it's very simple for me.
I have to wait for a clear evening to test if everything works; for now, it always gets cloudy in the evenings. I'll leave you feedback on this post as soon as I can.

Sequence.jpg (146.98 KiB) Viewed 2299 times

I can never thank you enough

Carlo